Diffusion-weighted echo-planar MR imaging of CNS involvement in systemic lupus erythematosus

Rationale and Objectives. The purpose of this study was to determine the ra nge of findings at diffusion-weighted magnetic resonance (MR) imaging in pa tients with systemic lupus erythematosus (SLE) and central nervous system i nvolvement. Materials and Methods. Diffusion-weighted MR images were reviewed in 20 pat ients with SLE and correlated with clinical symptoms and findings at comput ed tomography, conventional MR imaging, MR angiography, or conventional ang iography. Results. Diffusion-weighted MR imaging showed acute or subacute lesions in nine of 20 patients (45%). In the other 11, it showed no abnormal findings or chronic lesions. In four of the nine patients with lesions, diffusion-we ighted imaging primarily showed hyperintense lesions with decreased apparen t diffusion coefficient (ADC), which indicates acute or subacute infarcts. In four other patients, it primarily showed iso- or slightly hyperintense l esions with increased ADC, suggesting vasogenic edema. In two of these four patients, the findings were consistent with hypertensive encephalopathy. I n the other two, small hyperintense foci on diffusion-weighted images with decreased ADC were seen within the vasogenic edema. These foci presumably r epresent microinfarcts associated with SLE vasculopathy. In the ninth patie nt, diffusion-weighted imaging showed a small linear hyperintense lesion wi th normal ADC in the left parietooccipital region. Conclusion. Diffusion-weighted imaging shows primarily two patterns of acut e or subacute parenchymal lesions in patients with SLE: acute or subacute i nfarction and vasogenic edema with or without microinfarcts.